This invention relates to a container for transporting cleaned semiconductor processing equipment and, in particular, a pressurized container for maintaining such equipment in a fixed position during transport. Significant advantages of the invention are to reduce the opportunity for particle generation arising from movement of the equipment in the container and to eliminate contamination of the refurbished equipment by the entry of outside contaminants. Contamination of cleaned equipment during transport is likely to result in defects in the semiconductor products made in the equipment when again placed in operation.
In the manufacture of semiconductor products, a large diameter wafer is typically subjected to a number of processing steps. Among these steps are processes that sequentially add and remove materials from the wafer surface as well as implanting or defusing material into the wafer itself. The steps include the deposition of materials within a closed chamber onto the exposed surfaces of a masked wafer. While the portion of the wafer surface receiving the transported materials is well outlined, the movement of material from source to wafer is not fully controlled with the result that portions of the processing equipment adjacent the wafer target receive a deposit of material thereon. The deposited material initially adheres to the equipment, however, continued operation results in a buildup on the equipment. This buildup is not controlled and therefore often is non-uniform with the result that flaking and spalling can take place. To improve manufacturing yield, the equipment is periodically taken out of use, disassembled and the various parts transported to a cleaning facility. At this facility the parts are etched in a bath and otherwise cleaned to the original level of cleanliness. The particular cleaning process varies with the type of material being deposited.
The initial cleaning steps are concerned with removal of deposited masses of material and need not be performed in a clean room environment. However, the final preparation steps and the individual packaging of cleaned parts are carried out in a clean room environment, typically a class 100 room, where the quantity of airborne particles per unit volume is strictly controlled. Again the objective of the cleaning process is to return the parts to the manufacturing environment with a cleanliness factor that meets an objective standard so as not to reduce the manufacturing yield when returned to service.
The ever increasing complexity and reduction in size of semiconductor devices has made the manufacturing yield more important. Defects in an integrated circuit affect the operation of the circuit and render it unsuitable for reliable use. Circuits testing not up to standard are immediately discarded with little or no salvage value. Thus, the delivery of clean components to the reassembly point is a very important step in controlling yield.
Typically, after the physical removal of deposited materials, the equipment parts are transported in a water environment to the final packaging area. The components are usually wiped down and dried in an oven with a nitrogen environment. Packaging of the individual parts is conducted in a clean room. Each part is individually packaged for reassembly in the clean room of the manufacturing facility. The packaging of the individual components adds considerable cost to the cleaning process and delays the return of the equipment to manufacturing use.
Accordingly, the present invention is directed to a container for transporting assembled semiconductor processing equipment from the cleaning facility to the manufacturing user, thereby enabling the assemblage to be constructed in the clean room of the treatment facility and later opened in the clean room of the manufacturing facility. To avoid particle generation during transport, the container is provided with means for maintaining the relative position of the assemblage so that movement and incidental contact does not take place in the container. Furthermore, the container is constructed to permit a purge by an inert gas followed by an elevation of internal pressure to essentially eliminate the entry of contaminates from external sources during transport. After transport to the user facility, the exterior of the container is cleaned and the unopened container taken directly into the clean room.